One member, Lai Kuan Lin, called out a sasaeng — an over-obsessive — fan, saying, “Sorento (car), what were you doing below our home yesterday? Stop coming to our house.”

Another from the background said, “Dae-ddal-gak, only the pretty ones,” which means “Jerk off, only the pretty ones,” according to Allkpop.

Netizens immediately slammed Wanna One after the shocking broadcast, with many fans expressing disappointment at their idols’ display of inappropriate behavior. An Mnet staff confirmed that the video was streamed in error.

Realizing their mistake, the group penned an apology on their fan site (translation via Soompi):

“Hello. This is Wanna One. We are sorry and are writing to apologize directly to our fans who love and support us.”

“We are sorry for showing a poor appearance to our fans before the live broadcast today and disappointing you. We are reflecting deeply and we will try to always be careful and modest about all of our actions, as well as mature. We’ll work hard so we can show you a better image while always thinking of the undeserved love that you give us.”

“Once again, we are sincerely sorry to everyone for causing disappointment and concern.”

“We deeply apologize for the fact that an unfortunate incident occurred during the preparations for the Star Live broadcast today.”

“We are sorry for causing concern to the fans who have been loving and supporting Wanna One ahead of their comeback. We also think it is a shame that currently, even words that were not used in the videos that are circulating are being magnified and reproduced.”

“We will pay close attention so that similar incidents do not occur in the future. We ask for your interest and love so that the Wanna One members can follow their dreams.”